This does not require pre-existing formatted or linked text. The bug also appears if you enter the template first and then add bold word(s) immediately afterwards (no space between the template and the text), starting from an empty page or in a new paragraph.

For example, using VisualEditor with the intention of producing this, in this order:

{{unreferenced}}'''Hello world''' from Wikipedia.

actually results in this:

{{unreferenced}} from Wikipedia.

If you add a space or hit return after the template, then it works as expected.

HTML

<p><span typeof="mw:Transclusion" data-mw="{&quot;target&quot;:{&quot;href&quot;:&quot;Template:Inline&quot;,&quot;wt&quot;:&quot;Inline&quot;},&quot;params&quot;:{&quot;1&quot;:{&quot;wt&quot;:&quot;Foo&quot;}}}"></span><b>bar</b>quux</p>

Expected wikitext

{{Inline|Foo}}'''bar'''quux

Actual wikitext

{{Inline|Foo}}quux

:(

• This bug has been marked as a duplicate of bug 53434 ***

This is the same Parsoid bug that affected both places where we implicitly assumed that the 'about' id is always present (without realizing/checking that it could be absent for VE-inserted transclusions).